let s = "axc", t = "ahbgdc"
var isSubsequence = function (s, t) {
    let k = 0
    for (let i = 0; i < t.length; i++) {
        if (t[i] === s[k]) {
            k++
        }
    }
    if (k === s.length) {
        return true
    }
    return false
};
console.log(isSubsequence(s, t));
